Having used Joomla since it split from Mambo I can say that the author of this plugin should receive a medal or a donation of anyone that uses it a lot on their sites.
On issue - a lot of times i cannot get WMA files to stream at all. Also I find some mp3's play at "chipmunk" speed !! I think this is VBR or something in the way they are encoded ?? many a time I have had to re-encode an MP3 several times to get it working and sounding OK.
One thing though - what happened to the ability to add an image as a placeholder for video items?? I made one especially and it worked with version 2.1 but now I see no option for it.
I'm off to check the forum on the developers site... I could have missed something but I'm pretty familiar by now with it :)